using namespace std;
#include<iostream>
#include<signal.h>
#include<unistd.h>
void showSet(sigset_t *set)
{
    for(int i=0;i<32;i++)
    {
        if(sigismember(set,i))
        {
            cout<<"1";
        }
        else
        {
            cout<<"0";
        }
    }
    cout<<endl;
} 
int main()
{
    sigset_t set,old_set;
    sigemptyset(&old_set);
    sigfillset(&set);
    sigprocmask(SIG_BLOCK,&set,&old_set);
    cout<<"old_set:";
    showSet(&old_set);
    sigprocmask(SIG_BLOCK,&set,&old_set);
    cout<<"new_set:";
    showSet(&old_set);
    return 0;
}